1. Field of the Invention
This invention relates to electric motors, and particularly to reciprocating electric motors having permanent magnets with a reciprocating electromagnet cooperating with the permanent magnets.
2. Description of the Prior Art
Reciprocating electric motors have been known in the past. The Cobe U.S. Pat. No. 1,804,375 describes a reciprocating hermetically sealed compressor for use with a refrigerator or an air conditioner. One feature of this compressor is that it is hermetically sealed to prevent leakage of the refrigerant. Hence, the are no moving parts extending to the outside of the compressor housing, and this vastly simplifies the bearing packing problems. In this Cobe compressor, there is a central reciprocating piston having a pair of aligned piston rods projecting in opposite directions from each end thereof. A fixed electromagnet is positioned at each end of the compressor so as to cause the central piston to reciprocate. In order that the electromagnets may be alternately energized and de-energized to reciprocate the central piston within the cylinder, there is an automatically operated switch that is adapted to alternately make and break the circuit leading from the battery.
The Reutter U.S. Pat. No. 3,103,603 describes an AC synchronous reciprocating motor comprising an axially movable armature inside a field magnet fed with alternating current and subjected to the action of elastic drawback forces. The motor has a field magnet that includes two annular magnets made of ferrite having axial magnetization and between which is coaxially disposed the energizing coil that is fed with alternating current. The polarity of the magnets is symmetrical with respect to the transverse median plane, so that the flux reverses in the above-mentioned armature when it moves from one side to the other of the transverse median plane. There is a permanent magnet positioned at each end of the field magnet. Moreover, there is a coil formed as part of the field magnet between the two permanent magnets. One use described for this Reutter motor is that it actuates a fuel oil pump and an air-pump, both serving to feed a fuel oil burner.
The Olson et al U.S. Pat. No. 3,135,880 describes a linear motion electromagnetic motor wherein the armature may be positioned at any selected point within the limits of its stroke by means of an external control. This motor allows the armature to be positioned at a continuous infinite number of null points along the length of its stroke by means of a remote setting. This Olson et al motor may employ either direct or alternating current. This motor has a U-shaped core made of ferromagnetic material having two parallel legs joined at one end by a central segment to form two parallel deflection coils. Slideably mounted between the two deflection coils is an armature comprising a permanent magnet oriented so that the flux lines emerging from its ends cut the conductors of each coil at right angles. The armature is attached to one end of a connecting rod, and the free end of this connecting rod is provided with a coupling to which the motor is connected, such as a pump or the like.
The Lovell U.S. Pat. No.3,162,134 describes an electromagnetic pump having a central reciprocating piston that is controlled by a pair of electromagnets which surround the piston. It is noted that the energizing circuit can be powered from either an AC or a DC source, and that this piston pump or compressor is hermetically sealed.
The Drye U.S. Pat. No. 3,681,629 describes a reciprocating electric motor that has an armature shaft that is acted upon lengthwise by a moving magnetic field produced by a field device having stationary field part comprising windings interposed between sheet metal discs that are disposed around the armature shaft. A tubular member is rigidly secured over the field device. Means are associated with the armature shaft to enclose therein two liquid-filled hermetic enclosures through which the shaft extends, and which are connected by a limited-delivery duct so that the volumes of the enclosures vary in inverse proportion and by the same amount for a movement of the shaft in either direction.